Port Management
Link Aggregation
Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4 169
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• Static and Dynamic LAG Workflow
• LAG Management
• LAG Settings
•LACP
Link Aggregation Overview
Link Aggregation Control Protocol (LACP) is part of the IEEE specification (802.3az) that 
enables you to bundle several physical ports together to form a single logical channel (LAG). 
LAGs multiply the bandwidth, increase port flexibility, and provide link redundancy between 
two devices.
Two types of LAGs are supported:
• Static—The ports in the LAG are manually configured. A LAG is static if LACP is 
disabled on it.   The group of ports assigned to a static LAG are always active 
members. After a LAG is manually created, the LACP option cannot be added or 
removed, until the LAG is edited and a member is removed (which can be added back 
prior to applying); the LACP button then become available for editing.
• Dynamic—A LAG is dynamic if LACP is enabled on it. The group of ports assigned 
to dynamic LAG are candidate ports. LACP determines which candidate ports are 
active member ports. The non-active candidate ports are standby ports ready to replace 
any failing active member ports.
Load Balancing
Traffic forwarded to a LAG is load-balanced across the active member ports, thus achieving an 
effective bandwidth close to the aggregate bandwidth of all the active member ports of the 
LAG.
Traffic load balancing over the active member ports of a LAG is managed by a hash-based 
distribution function that distributes Unicast and Multicast traffic based on Layer 2 or Layer 3 
packet header information. 
The device supports two modes of load balancing:
• By MAC Addresses—Based on the destination and source MAC addresses of all 
packets.
• By IP and MAC Addresses—Based on the destination and source IP addresses for IP 
packets, and destination and source MAC addresses for non-IP packets.